Improvement in valve-gear of steam-engines



UNITED STATES `PATENT OFFICE.

IMPROVEMENT IN VALVE- GEAR OF STEAM-ENGINES.

p Specification forming part of Letters Patent No. 37,342, dated January6, 1863.

.To a/ZZ whom it may concern:

Be it known that l, W. R. GEEENLEAF, of Silver Creek, in the county ofChautauqua and State of N ew York, have invented certain new and usefulImprovements in the Valve- Gear of Steam-Engines 5 and I do herebydeclare that the following is a full, clear, and exact description ofthe same, reference bei ing had to the accompanying drawings, formingpartof this specification, in which- Figure l is a side view of a doublemarine- Y propeller engine having myinvention applied, the shaft beingrepresented in section. Fig. 2 is a vertical section of the principalportions of the valve-gearlengthwise of the shaft. Fig. 3 is alongitudinal outside view of a portion `of the same. Fig. 4 is a diagramillustrating the operation of the eccentrics.

, Similar letters of reference indicate corresponding parts in theseveral figures.

This invention consists in a certain arrangement of valve-connectionswhereby a single eccentric is rendered capable of operating the twoinduction andeduction valves ofa double engine with suitablyarrangedcylinders.

It also consists in certain novel and simple means of shifting theeccentric for the purposes of varying the length of travel and reversingthe movement of the valve, whereby a single eccentric is made to effectin a better manner all that is effected by two eccentrics and alink-motion.

To ena-ble others skilled in the art to make and use my invention, Iwill proceed to describe its construction and operation.

A is the framing of the engine, and B B are the cylinders set atopposite inclinations in a plane or planes perpendicular to thecrank-shaft C, and having the piston-rods 4working through their lowerends to be connected with the crank-shaft, whichis arranged below thecylinders. The cylinders are supposed to be fitted with oscillatingvalves, the stems a a of which are represen ted in Fig. l as furnishedwith crank-arms b b', connected by two rods, c c', with the ring E ofthe single eccentric D. One of these rods, o, is rigidly attached to theeccentric-ring, but the other is attached by a pivot-joint, d, as somelittle play is necessary between the two rods. The arrangement of thevalves and their crankarms b b is such that the two eccentric-rods c cwill, when either valve is at half-stroke,

be at the same angle` to each other as the cylinders B B', and by thatmeans the single eccentric is made capable of working the valves of thetwo cylinders. llt is to obtain on the shaft, or be movable for thepurpose of reversing the engine or varying the stroke of the valve. Theeccentric D is movable, and its movement is provided for in thefollowing manner:

F is a disk fast upon and concentric with the crank-shaft and having inits face a slot or slots, f, running parallel with the line in which theeccentric D is t be moved to reverse or vary its throw. The eccentric ismade with a tongue or tongues to fit and slide in this groove and isprovided with an elongated opening, g g, the parallel sides of which areat right angles to the length of the tongues e and grooves f, suchopening receiving a smaller eccentric, G, which is fast upon a sleeve,H, which is fitted to turn easilyT on the crank-shaft C. This eccentricG, which may be termed the inner eccentric,to distinguish it from themain eccentric, D, ts snugly be1 tween the sides of the opening g g, sothat it will be caused by any movementof the sleeve H around the shaftto shift the main eccentric in a direction parallel with the tongues andgrooves e f. Whenthe inner eccentric, G, is turned to a position inwhich its eccentricity to the crank-shaft is in a direction parallelwith the sides of the opening gg and at right angles to the tongues andgrooves e f, the main eccentric will be brought to a position only justsufficiently eccentric with the shaft, as illustrated in black outlinein Fig. 4, to operate the valve the distance of its lap and lead, andthus will cause the stoppage of the engine, but by turning the saideccentric G either in one direction or the other from this position itwill give the main eccentric a greater throw in the correspondingdirection,

as illustrated by red and blue outlines in the same gure, and make itgive steam to the engine for working in one direction or the other, andhence the single main eccentric is made capable of effecting all that iseffected by two eccentrics with a link-motion, and by using this mode ofshifting the eccentric, in combination with the system of eccentric-rodsand valve-connections hereinbefore described, a single eccentric is madecapable of effecting all the necessary movements of the valves of adouble marine-en gine.

To provide for the turning of the sleeve H while the engine is in motionthere is fitted to the exterior of said sleeve a second sleeve, I, aportion of which is also tted to feather, h, on the crank-shaft, so thatthe said sleeve I is compelled to turn with the said shaft, thoughpermitted to slide longitudinally thereon, as well as upon the sleeveII, which is prevented from having a longitudinal motion. The sleeve H'has cut in its eX- terior a spiral groove, c', and the outer sleeve, I,has secured in it a pin, j, which enters the said groove, and whichshould be fitted with a slide, K, or roller, fitting easily into thegroove i. .The outer sleeve, I, has also provided in it acircumferential groove, le, for the reception of the forked end of ,alever, which works on aXed fulcrum, and by which the longitudinalmovement of the said sleeve may Abe effected. In this longitudinalmovement the pin j, by'its movement along the groove c', produces themovement of the sleeve H around the shaft.

In applying the movable eccentric, operated as above described, tolocomotive-engines, the arrangement of the cylinders renders itnecessary to have a separate main eccentric, D, for operating eachvalve, and each main eccentric requires a separate inner eccentric, G,one on each end ot sleeve H.

Some of the advantages which this system of valve-gear has over the twoeccentrics and link-motion may be enumerated as follows: First, it ismore simple and of less expensive construction; second, it has fewerparts, weighs less, and takes up less room, all very importantconsiderations in a locomotive; third, it gives a better and moreperfect movement, obviating the inequality of movement and variation oflead which are unavoidable with the link-motion fourth, it is lessliable to get out of repair and more easily kept workin gsteam-square;77 fth, it is more easily reversed, and more easily held inany desired position.

What I claim as my invention, and desire to secure by Letters Patent,is-

1. The combination and arrangement of the valves, valve-stems, or valverock-shafts,

and ofthe two eccentric-rods c c', attached to the same eccentric,substantially as herein described, whereby the one eccentric is made tooperate the valves of both cylinders of a double engine, as herein setforth.

2. The employment, for operating the inner eccentric, D, of two sleeves,H I, the one moving around and the other sliding longitudinally upon thecrankshaft, the two combined by a spiral groove, i, and pinj, and thewhole operating substantially as herein specified.

W. R. GREENLEAF. Witnesses:

HENRY WHEELER, Trios. G. MoRsE.

